Antarctica

Antarctica, fifth largest continent, almost 6,000,000 sq mi (17,400,000 sq km). Antarctica is almost entirely covered by an ice cap up to 14,000 ft (4,267 m) thick except where the ice is pierced by mountain peaks.

The Vinson Massif is Antarctica's highest mountain (16,900 ft /5,150 m). The continent is circular, indented by the arc-shaped Weddell Sea (south of the Atlantic Ocean) and the rectangular Ross Sea (south of New Zealand). Pack ice virtually surrounds the rest of the continent. The western half of Antarctica, including the Antarctic Peninsula, is structurally related to the Andes; the eastern half geologically resembles Australia and South Africa. Antarctica is almost entirely within the Antarctic Circle (66°30' S) and the climate is intensely cold, with winter temperatures as low as −80° F (−62° C), and winds up to 100 mph (161 kmph).

Capt. James Cook was the first to attempt a scientific exploration of the region (1773). The mainland was probably first sighted in 1820 by the American sea captain, Nathaniel Palmer. The Englishman James Weddell led an expedition to the area in 1823 and another Englishman, James Clark Ross, discovered the sea later named for him. The Norwegian Roald Amundsen was the first to reach the South Pole on Dec. 4, 1911 and Admiral Richard Evelyn Byrd became the first to fly over the pole on Nov. 29, 1929. Since the International Geophysical Year (1957–58), international cooperation in Antarctica has increased. On Dec. 1, 1959, 12 nations signed the 30-year Antarctic Treaty reserving the area south of 60° S for peaceful scientific investigation. In 1985, 32 nations agreed to limit access of humans to Antarctica to specific research sites. Antarctica is home to over 25 scientific installations, three of which are from the United States. During the 1980s scientists began to detect a deterioration in the ozone level above Antarctica which created great environmental concern for the region and the planet. The ozone layer protects the planet from destructive sun rays. Because of this new awareness and increasing accessibility to the region, tourism to Antarctica is rising.